Rolling mill and bearing therefor



Mgy zo, 1941.

A. KINGSBURY ET AL ROLLINC- MILL AND BEARING THEREFOR 16 lllllllllllllllllllllll Filed Jan. 26. 1954 14 .Sheets-Sheet 1 16 IIIIIMEMLIIIIIH May 20, 1941.

A. KINGSBURY `E-r Al.

.ROLLING MILL AND BEARING THEREFOR Filed Jan. 2e, 1934 V 14 Sheets-Sheet 2 nventors Gttornegs I Mayzo, l1941. A KWGSBURY ETAL 2,243,009

ROLLING MILL AND BEARING THEREFOR Filed Jan. 26, 1954 14 sheets-sheet 5 Gttorneg Snvmtors May 20, 1941- A. KINGSBURY E-'AL 2,243,009

ROLLlNG MILL AND BEARING THEREFOR Filed Jan. 26. 1934 14 Sheets-Sheet 4 A. KINGsB'URY YETAI. 2,243,009 ROLLING. MILL. ANDr BEARING THEREFOR May 2o, 1941.

FiledfJangfzs, 1934 14 sheets-'sheet 5/ May 20, 1941. A. KING'sBuRY Erm. 2,243,009

K ROLLING MILL AND BEARING' THEREFQR Filed Jan. 26, 1934 14 Sheets-Sheet `6 May 2 0, 1941 A. KnmsaumY E-rAL 2,243,009

ROLLING MILL AND BEARING ,THEREFOR v Filed Jan. 26, 1934 14 sheets-sheet 7 May zo, .1941. A, KINGSBURY ETA.. 2,243,009

V ROLLING MILLl .ANDI BEARING THEREFOR Filed' Jah. ze, 1934 14 sheets-sheet s May 20,--'1941... A. K'INGSBURYIETAL f. I 2,243,009 ROLLING MILL AN BEARING` THEREFOB A Filed Jan. 26, 1934 14 sneetssshe'et 1o May 20, 1941- n l A.YK|NGsBURY ETAL 2,243,009

LLING MI www MayZO, 1941. A. KINGSBUBY ETAL `A 2,243,009

ROLLING MILL AND' BEARING THEREFOR Filed Jail. 2s. 1954 14 sheets-sheet 12 May 20, 1941 A. KINGSBURY Erm. 2,243,009

ROLLING MILL AND BEARLNG THEREFOR- Filed Jan. 26, 19s4 14 sheets-sheet 13' May 20, 1941., A.VK|NGsBuRY EAx. ,n y 2,243,009

ROLLING MILL AND BEARING THEREFOR Filed Jan. 26, 1934 14 Sheets-Sheet 14 Patented May 20, 1941 2,243,009 ROLLING MILL AND BEARnvG rnannson Albert Kingsbury, Greenwich, conn., mi Harry A. S. Howarth, Philadelphia, Pa., assignors, by mesne assignments, to Mesta Machine `(Jom- UNITED STATES PATENT vOFFICE rolls can prevent these variations.

INDY. West Homeste Pennsylvania ad, Pa., a corporation of Appucstion January 2s, 1934, sesamo. 708,501

(ci. :so- 55) 83 Claims.

ience, the bearings will be chiefly described with particular reference to their application to the necks of the backing-up rolls, but as will be apparentto those skilled in the art, certain features of the invention are applicable to bearings to be expressly understood that the description of the invention as applied to the necks of the backing rolls of a four-high mill is not to be construed as excluding any other suitable use of the invention as hereinafter defined.

The primary object of the present invention is to-provide a rolling mill with improved radial -oil film bearings, the term "oil film" bearing being used to differentiate from bearings of the so-called antiiriction" type, such as roller bear- 11118.

The passage of the -rollers of an antifriction bearing through the load region has been found by experience to cause variations ln the thickness of the plate or other element being rolled, apparently due to the alternating variations in the distribution of the load as the resultant alternately passes through a roller or between two rollers. 'I'hese variations in thickness arise even though there is perfect accuracy in the concentrlcity and nt of the bearing parts, but experience has demonstrated that it is very dimcult to get bearing races which are perfectly Cil - for the necks of working rolls. Therefore, it is concentric as to the outside and insidel diam.-

eters. Inaccuracies in the diameters of theraces. particularly of the inner raceproduce variations rolled, and no accuracy in the grinding of the rollers` frequently become slightly oval or elliptic with use, and even though. the diameters of the races are accurate, such oval or elliptic rollers tend to produce a marking of the plate by infinitesimal variations in thickness which may affect the saleability of the plate for some purrolling mill with improved radial oil film bearings whereby the foregoing variations 'in thickness and markings of the plate or other element being rolled are avoided.

The reduction of they metal going through the pass is a function of the speed of the rollsr Therefore, variations inA roll speed produce vari-.- ations in the gauge of the rolled metal. Hence the control of the gauge under `changing roll vspeed is of very great importance, especiallywhen it is remembered that under present practic as much as 20% of the rolled sheet is frequently found not to be of correct gauge, and therefore can only beisold at a reduced price.

,With oil film bearings the thickness of the film,

other things being constant, isV also a function of the speed, the iilm increasing with increase' of speed. 0n the other liand, increase. in speed of the workingrolls' tends to decrease the reduction. It is therefore an object of this inven- .ness of the voil films will vary with the roll speed,

inversely to the tendency of the vchanging roll speed to vary the gauge.`so that the latter effect may be compensated by the variations in roll pressure thereby produced by the automatic variation of the supply of oil to the bearings.

The variations in oil film thickness or pressure .as a compensating factor for variations in gauge accompanying variations in roll speed depend in part upon the viscosity of the lubricant and in part on the extent to which the rolls and their supporting housing can be flexed or stretched. The latter. for any installation. is a substantially ilxed quantity, but the viscosity of the lubricant may vary under changes in temperature. AImother object of this inventionvis to provide a rolling mill with radial oil film bearings wherein the temperature of theoil is varied-automatically to aid in or provide for the foregoing compensating actions.

Another object of thisjinvention is to provide a rolling mill with radial oil nlm bearings wherein changes in oil film thickness or pressure arev employed to compensate for variations of gauge from the necks of thickness lwith variations in speed and the viscosity of the oil is kept substantially constant by changing the cooling of the bearings simultaneously with the change in heat losses due to a rolling mill with improved radial oil illm bearings to the end that the accuracy of gauge of the plate or other element being rolled may be maintained. l

Another object of this invention is to provide a device of the type lust characterized wherein the bearings are provided with adequate lubrication.

Another object of this invention is to provide a l device of the type just characterized wherein the bearings and roll necks are maintained at a proper temperature.

Another object of this invention is to provide a rolling mill with improved radial oil film bearings wherein the bearings are so mounted as to which require a minimum change in the construction of the mill, and which may therefore be readily installed in mills already in service as well as provided in mills newly constructed.

Another object of this invention is to provide a rolling mill with improved radial oil film bearings and with means for properly protecting the bearing surfaces on the rolls when the associated bearing elements are removed.

Another object of this invention is to provide a rolling mill with improved radial oil film bearings which may be readily assembled and disassembled without injury to the parts.

Another object of this invention is to provide a rolling mill with an improved radial oil film bearing which may be adequately lubricated without excessive oil consumption and which is so constructed as to protect the bearing surfaces against ingress of foreign material during operation.

Another object of this invention is to provide a rolling mill with means associated with the roll bearings whereby the rolls and bearings may be readily inserted into and withdrawn from the mill frame as a unit without undue stress being imposed on the roll or the bearing parts.

Another object of this invention is to provide improved bearings for rolling mills which are give suitable freedom to the rolls, bothwith reing which has associated therewith a suitableA thrust bearing for sustaining the axial thrust on the roll.

Another object of this invention is to provide a device of the type just mentioned wherein the thrust bearing does not interfere improperly Y with the expansion and contraction of the roll and its associated parts.

Another object of this invention is to provide a l rolling mill with improved radial oil nlm and thrust bearing elements so associated therewith as to be readily mountable on and demountable from themill in unitary relationship with the rolls.

Another object of this invention is to provide a device of the type iust mentioned wherein the rolls may be stored with the bearing elements as sembled on their necks in unitary relationship therewith, and whereby said bearing elements will suitably protect said necks during storage or during grinding of the rolls. s

lAnother object of this invention is to provide a device of the type just referred to which is so constructed as to prevent the development of undue stresses in the parts during the mounting ang demounting of the rolls with respect to the m Another object of this invention is to provide a device of the type just referred to wherein the bearing elements may be readily removed the rolls for inspection or repair.

Another object of this invention is to provide a rolling mill with improved radial oil film bearings which may be employed with sleeves suitably mounted on the roll necks.

Another object of this invention is to provide a rolling mill with improved oil film bearings highly efllcient in service, compact in structure, and strong and rugged. in operation, and which also possess various improvedieatures in their lubricating and cooling systems.

Other objects of the invention will appear hereinafter from the detailed description of embodiments thereof as illustrated on the drawings.

The invention is capable of receiving a variety of mechanical expressions, some of which have been shown on the accompanying drawings for the purposes of exempliflcation, but it is to be expressly understood that the drawings' are for purposes of illustration only and are not to be construed as a definition of the limits of the invention, reference being had to the appended claims for that purpose.

Referring in detail to the drawings, wherein the same reference characters are employed to designate corresponding parts in the several ng- Fig. 1 is a somewhat schematic elevation of a rolling mill of the four-high type, showing in section the inner bearing of the upper roll and the outer bearing of the lower roll constructed in accordance with .the present invention;

Fig. 2 is a transverse section of the structure of Fig. 1;

Fig. 3 is an enlarged axial section of the embodiment of this invention applied to the outerneck of a backing roll;

Fig.- 4 is a corresponding section of the bearl lchuck;

Fig. 10 is a diagrammatic transverse section illustrating the separation of the chuck parts vfrom the bearing shell;

Fig. 1l is a` schematic view on a reduced scale to illustrate the manner in which the unit com- Y y 1 9,249,005 posed of roll, bearings and chucks is retained in i the frame:

Fig. 12 is a schematic view on a reduced scale to illustrate means for protecting the `roll neck when the cooperating bearing parts have beenl Fig. 13 is a somewhat schematic view to i1- lustrate the means used to remove the roll unit and also showing the roll with its chucks removed and the bearing'elements'on the neck in proper position for storage or grinding;

Figs. 14 and 15 are schematic views on a smaller scale `illustrating an alternative manner ofy mounting the bearing sheus in the chucks Fig. 16 is a schematic view of a protecting sleeve for the roll neck with which a thrust bear- -ing is associated;

of the character indicated in Figs. 14' and l5:`

Figs. 19 and 19a are axial sections ofthe ends l of a roll 'neck bearing of somewhat diiierent construction than shown i'n Fig. 18; l

Figs. 20 and 2l are axial and transverse sec-` tions of another embodiment of the invention applied to a lowerroll; Fig. 22 is a view corresponding to Fig.` 21 but showing the invention applied to an upper roll; and

Fig. 23 is a view to illustrate protection of the radial bearing surfaces'during grinding or turningoftherolL v.

In the form of mill shown in Figs. 1.and.2 the working rolls are designated Il and provided between the same the pass il for the material to be rolled. The mill illustrated is of the fourhigh type, and therefore each of said rolls il isl sleeve on the roll neck and shell retaining means Figs. 1 and 2.

In conformity with the present invention each roll neck is carried by a bearing of the radial oil nlm type, and associated with' each roll, adiacent the radial oil nlm bearing at the outer neck thereof, is a thrust bearing, preferably also of the oil nlm type. the present invention permitting the use of a single thrust bearing for each roll.

In rolling metal strip from a slab, the extent .of the reduction ofthe'metal decreases with an increase in the-speed of said rolls. Hence the changes of speed which occur `during the period when themill is ystarting and stopping, and any variations in speed while the mill is in operation, cause changes in the gauge of the material being rolled. An oil-film bearing, on the other hand. the characteristic that the thickness of the nlm increases with the speed of rotation oi the relatively movable bearing parts. By suitably selecting the viscosity of the lubricant the oil-nlm bearing can be so constructed that the increase in nlm thickness with increase of roll speed largely if not exactly compensates for the increase in gauge which accompanies such change in roll speed.

We do not rely. solely on automatic change in film thickness with change of roll speed.' The oil film bearing possesses'the further advantage that this effect may be supplemented and controlled by changing .the rate of supply or the pressure of the oil supplied to the bearing so that by exteriorly regulating the oil supply, -the oil film may be changed to compensate for the change in gauge that would otherwise arise from change in may be augmented by use of high-pressure oil backed by a roll I2 of substantially larger dii ameter than the working roll. 'In mills of the type illustrated the working rolls Ill are positively driven, as by a motor, through the ilexible cousize and strength.

The present invention s lparticular utility when applied to the bearings of said backing rolls, and is illustrated and described as apv plied to such use. Said rolls are commonly mounted to be moved into and out of their .approximately operative positions in the direction of their axes, and lto this end the bearings at the necks of the respective rolls are carried by suitable chucks which are locked in the housing as hereinafter explained in detail. The mill is provided at each end of the upper backing roll with a screw I5 (Fig. 2). driven by gearing il for regulating the pressure between the working rolls and thereby varying the pass. said screws being shown as having indicating graduated disks I1 and'seating in the recesses of cup-like members il which engage the hereinafter described tiltable bearing blocks for the bearing shells oi' the upper .backing roll bearings. As the. ,construction of the mill outside of the units composed of the rolls whose rate of application or supply maybe under the control of any suitable variable such as roll speed, cooling water temperature, etc.

The present invention therefore involves the method of automatically compensating for changes oi' gauge that would otherwise arise from changes in roll speed by changes in the pressure ot the oil illm, whether arising solely from the change .in film vthickness accompanying change in the speed of the roll, or caused or supplemented by a change in the pressure or in the rate of supply at which high-pressure oil is applied to the bearing. For example, if the change in the, oil nlm thickness is too great or too small upon change' in roll speed. the desired oil-nlm thickness can be maintained by changing the'rate of supply or the pressure of the oil being supplied to the bearing. Thus the rheostat or other control for the motors which drive the rolls canjv be suitably connected with the high-pressure pumps which supply the oil to the oil films so that tion is dependent in part upon the viscosity ot the oil. Increased speed is accompanied by increased friction losses and heat generation in the bearings which may result in turn in a-change in the viscosity of the oil. The present invention also includes the method of varying the cooling at the bearing so that the same viscosity will be with their associated bearing elements and parts maintained or the change in viscosity may be suitably controlled. Thus as speed increases, the

circulation of cooling water in heat interchangingv relation with the vbearings should increase to carry away the increase in heat losses arising from friction if the oil viscosity is to be maintained constant, and therefore the rheostat or other control which determines the speed of the `motor may be suitably connected to the watercirculating pumps so as to vary the circulation of cooling water as the speed of the rolls is changed, or the temperature of the water may -variable film thickness which will produce the desired compensation for the tendency of the gauge to vary.

In addition to the foregoing advantages possessed by an oil-'film bearing, is the vfact that the distribution of pressure over the bearing surfaces is regular, i. e., there is no irregular or periodic change in concentration or distribution of pressure such as exists, for example, in a roller bearing when the resultant of the pressurepasses relatively from the radial plane of the axis of a roller to a plane intermediate the radial planes of the axes of adjacent rollers. Hence not only does the present invention eliminate difficulties heretofore experienced with respect to changes in gauge arising from changes in roll speed, and losses due to gauge change when the mill is being brought into operation and stopped, but the present invention also eliminates those changes in thickness which arise when antifriction bearings are used. p

Furthermore, use of a radial oil-film bearing permits the employment of high-pressure oil on the roll bearings when the mill is put in operation, and thereby the heavy wear incident to starting friction is very largely overcome. In mills of the type under discussion, the working rolls are ordinarily driven directly, and the backing mils are driven by friction. If the screws which determine the gauge thickness are tightened so that the sur.. face friction between the working and backing rolls is suilciently great, the Working rolls when positively driven will drive the backing rolls and thereby overcome the starting friction in the bearings of the latter. If there is slippage between the rolls in starting, this wears the ro'lls, and if the friction is so great that no slippage can occur, there still remains the heavy wear in the bearings of the backing rolls.v at starting.

.By `using high-pressure oil during the starting period an oil nlm may be preliminarily established i between the bearing surfaces of the backing-roll bearings so that starting friction is reduced to a minimum. However, if preferred, this use of high-pressure oil at the starting may be omitted, and the invention still possesses important advantages as above discussed with respect to maintaining uniformity of gauge etc.

The present invention also permits the omission of sleeves on the necks of the rolls, and thereby the elimination of the difilculties heretofore experienced in grinding the sleeves exactly concentric with the roll necks, in the tendency of the sleeves to creep, etc. The necks of the rolls as ordinarily constructed are suiliciently hard so that with the use of a proper oil film between the'bearing` parts there is no excessive wear.

However, if preferred, the necks of. the rolls maybe provided with sleeves of any suitable character and construction and mounted on the roll necks in any suitable way. As illustrated, some of the embodiments use the surface of the neck itself as the bearing surface While in others a sleeve is employed, but it is to be expressly understood that either construction may be used in embodiments of this invention. Y

Referring now more .particularly to the first embodiment shown on the drawings, Figs. 3 and 4 are complementary views showing the improved radial oil-nlm bearings applied to the necks of the lower roll and with a thrust bearing disposed adjacent the radial bearing at the outer neck of the roll, but it will be understood that the upper roll is provided with similar bearings but with the bearing shells inverted to accord with the reversal in thev direction of the pressure. Roll I2l has the usual necks 20 and 2| with which cooperate the radial oil-film bearings next to be described. Projecting beyond the neck 20 is a portion 22 of smaller diameter, said portion adjacent the outer neck having associated therewith the thrust bearing to be described, and `beyond said portion 22 is a portion 22 of a diameter somewhat smaller than the portion 22 and which may be designed for engagement with the conventional hook employed in mounting and demounting the roll.

Cooperating with the bearing surface provided by the cylindrical surface of the neck 20 and mounted' in a chuck generally designated 24 is a bearing shell 25 which, as shown at the left in Fig. 5, may have its outer surface eccentric with respect to its inner bearing surface 26, with the thicker portion of the bearing shell thus provided disposed at that side of the neck which'is removed from the working rolls. The inner bearing portion 26 may be of. any suitable material, character, and form, depending upon the service to which the bearing is to be put. At its opposite ends bearing shell 25 is provided with flanges 21 and 28 l(Fig. 3). Flange 21 has suitably attached' thereto, as by screws 21', a ring 29 which carries an oil retaining ring 30 cooperating with the peripheral surface of the` neck, the end of the roll being shown as provided with a recess 2| to receive the oil retaining ring 29, 30

and said roll also having an axially extending flange 32 for cooperation with an oil retaining ring 33 on the chuck.

Bearing shell 25 is pivotally mounted within the chuck for axial tilting by a generally rectangular supporting block 34 having a dowel projection 34' which enters a corresponding recess 35 in the shell and which, as shown in Fig. 9, may have four raised portions 38- symmetrically disposed to make bearing engagement with a flat surface 31 on the shell. In order to minimize interference with the tilting of the bearing shell 25, said shell at' its upper portion is shown as having only an-axially narrow contact at 25' f with the bore of the chuck. Contact between the bearing shell and chuck at this point may be reduced to zero if'the shell is otherwise suitably supported within the chuck. Bearing block 24 has contiguous'to the inner extremity of its lateral surfaces a pair of opposed finished surfaces 38 (Fig. 5) at its two sides which are lateral with respect to a vertical plane through the axis of the neck and which engage corresponding finished surfaces in the aperture 39 provided in the chuck for said block. Said bearing block also has conaia-sacos tiguous to the outer extremityof its lateral surface a pair of opposed finished surfaces 4l! (Fig. 3) at its two sides which are spaced axially of the neck and which engage corresponding finished surfaces 4l in said aperture 89. The outer surface of said bearing block has a centrally and transversely disposed curved or tapered boss or knife edge 42 adapted to engage a hardened plate or distance piece 43 suitably mounted on the housing (Fig. 1) thereby providing a pivotal axis on which the bearing shell may tilt freely in the direction of the axis of the neck to permit proper alinement of said shell with the neck under such deflection as unavoidably arises from 'the pressures involved. At the same time said dowel b lock, with its aforesaid surfaces of engagement collar 84 with one pair on each side of the neck and with the shoes of each pair symmetrically arranged with respect to the horizontal plane through the axis o'f the neck. The shoes 88 are tiltably mounted on the radial face 81 of the ring 4l and on the radial face 88 of the ring 48,

an'd suitable dowels or pins 89 prevent improper with the chuck, prevents rotation and other imvproper displacement of the bearing shell with respect to said chuck. As shown, said block also has overhanging shoulders 44 which may engage the chuck around the opening 28 so that the block will be retained in the chuck when the chuck ls removed from the mill with the roll.

Flange 28 projects axially beyond the shell 28 and has its inner overhanging surface 48 in cooperation with an oil retaining ring. 48 suitably mounted on a ring 41 which is attached in any suitable way, as by screws 48, to a ring 49 which provides with said ring 41 a housing for the thrust bearing at the outer neck of the roll. In order to secure said thrust lbearing housing to the bearing shell 28 and also to close up the gap which normally is' left at 88 to permit relative axial. movement between the bearing shell 28 and the housing for the thrust-bearing, flange 28 is also provided with stud bolts 8l 'whichy have threaded engagement with the ring 41 and pass freely through apertures in the ange 28.- As

displacement of the shoes. In the bearing as illustrated, no provision for equalization of pressure between the thrust bearing shoes is shown,

but it is to be expressly understood that if preferred any suitable form of equalizing means,

Mounted within the outer end of the ring 48, V l

and suitably secured therein as by screws 8l is a ring 82 which carries oil retaining rings 88 and 84 at axially opposite sides of a recess 88 therein and which is in open communication with a recess 68 in the ring 49.

shown, said housing ring 48 is normally 'supported by' and located with respect to the chuck by the engagement of a peripheral ange 49' on the ring in a corresponding peripheral recess in the chuck.

Thereby the thrust load of the thrust bearing is transmitted'in its entirety to the chuck; and

none of said load istransmitted to the bearing shell. At the same time the iointbetween the inner periphery 48 ofthe ring 28 and the oil retaining ring 48 permits axial tilting of thebearneck as by a key 8l. Formed on or suitably attached to said sleeve 82 is a flange 84 which constitutes the thrust collar. Cooperating with the` opposed facesof said thrust collar are suitable thrust receiving bearing members, preferably of the surface bearing type, and here shown as shoes 88 ofthe Kingsbury type tiltably mounted at'58 in a manner well understood in the art. to form wedge-shaped oil films between the bearing faces of said shoes and the bearing faces of said collar. It is to be expressly understood. however, that in place o fa plurality of shoes other suitable forms of thrust bearing may be employed. For example the stationary bearing members may take the form of self alining washers having spherical rear surfaces engaged in correspondingly shaped seats, particularlyif one of each pair ofcooperating bearing surfaces is grooved -andbeveled adjacent the grooves to facilitate the forming of the oil slms. As shown.

two pairs of shoes 88 ensaseeach face of the the loaded side of the bearing surfaces.

As shown, the portion 22 of the neck is also provided with a collar 8l, suitably retained theref on as by a ring nut 88 engaging a split threaded collar 69 held in a groove 89' in neck portion 22, for a purpose hereinafter explained. When ring nut 88 is tightenedl up, the thrust bearing sleeve 82, through collar 81. is clamped against the shoulder 'I8 between the portions 2li and 22 of the neck. In some -cases the collar 81 may be omitted, in which event the ring nut 88 may enf gage directly with the end of the sleeve 82.

'I'he inner or bearing face of the shell 28 is I cut away as indicated in dotted lines at 1| in Fig. 3, said cut away portions being approxi` be a complete annulus except for the gap at 18. As shown, an oil retaining ring 14 is also pro'` vided for cooperation with the low-pressure half of the annulus 12, adjacent to but axially inside of the oil retaining' ring 80. By using a halfring seal as shown a relatively large clearance may be usedat the bore of the Igap without a corresponding loss of 'oil by leakage o r a lose ofefi'ective length in the directionof the axis of Said ring'member 14 may be retained in position in any suitable way, as by springs at the ends thereof acting generally -tangentially but with a radial component. At the opposite end of the shell the radial bearing surface is in communication with an annular space 18 which in turn is in open communicaiion with chambers 1e within which are disposed the thrust bearing members: The mein oil Supply for theradial bearing enters the thrust-'- casing chambers, as shown at. 11 in 1113.5, and fromthese chambers the .oil may flow` freely through theannuiar space 18 to the radial beer.-

ing surfaces, nlling the pockets 1| and-providing an oil nlm between the bearing surfaces of the neck and bearing shell.

. This supply of oil may be a gravity-feed supply. When oil under high pressure is also furnished to the radial bearings for reasons heretofore ex.-

1s, and through a' suiiabie pipe extension n heid A at its inner-end in a socket in the end of the bearing shell by a threaded thimble 8|..l Said matically indicated at 8|.

. each circle being equidistant from and on opposite sides of the plane through the axis of the roll which contains the resultant of pressure. The provision of these points of delivery of the highpressure oil may be considerably varied, but it is desirable that the high-pressure oil be introduced symmetrically with respect to the four points of support 36 on block 34 so that the pressure has no tendency to spring the bearing surfaces out of shape. Oil so supplied un'cier pressure may be used either to establish an oil film between the bearing surfaces for the purpose of reducing starting friction or to control the thickness of the oil film in the compensation of the effects of varying speed as heretofore explained in detail.

Whether or not the main oil supply is formed by or supplemented by a high-pressure oil supply, the chambers 16 and 15, and the oil pockets 1| are normally maintained full of oil. From this oil a film forms between the bearing surfaces of the neck and the bearing shell during rotation. Leakage of oil past the annulus 12 is restricted by half ring 14, but such oil as passes said annulus is caught in the annular cavity 84 and is largely prevented from escaping by the oil retaining ring 36. If high-pressure oil is used, there may be an excess pressure on the oil in the cavity 84, but this is advantageous as it tends to prevent water and dirt from getting from the outside into said cavities and onto the bearing surfaces. 'Oil passing into said cavity 84 flows through passage 85 into annular cavity 86 in the chuck and may be returned to the oil supply through pipe 81 suitably secured to an outlet passage in the chuck. Since water cooling is employed as hereinafter explained, no circulation of the oil is necessary, and the oil flowing through cavity 84, passage 85, cavity 86 and pipe 81 is only such pil as leaks past the annulus 12, and as this oil is uncontaminated, it may be returned to the sump for use over again. It will also be noted that any oil escaping past the oil retaining ring 46, between the bearing shell and the thrust bearing housing, will also flow into cavity 86, this also being uncontaminated oil.

Any oil escaping past the oil retaining ring 30 into cavity 3| may be led away through drain pipe 88. Any oil leaking past the oil retaining ring 63 is collected in the chambers 65 and 66 which form an oil seal and from those chambers oil is returned to the system, as it is uncontaminated, through a suitable passage leading to chamber 86. Any oil escaping past oil retaining ring 84 may be collected in the housing 88, provided to exclude water, dirt, grease, etc. from the outer end of the neck and suitably secured to the chuck as by screws 9D, and flow therefrom through a drain connection such as diagram- Oil from drain connections 88 and 8| is likely to be contaminated because of water and dirt working past the oil retaining ring 33 or into the housing 89, and hence should not be returned to the sump.

As heretofore referred to, provision is made for suitably cooling the bearing shell 26 so that the viscosity of the oil will be suitably controlled. As

y in the chuck 24.

illustrated, the thicker half of the bearing shell 25 is provided with a series of axially extending communicating passages 92. The bearing shell may be made of forged steel and a groove may be machined in each end of the shell as shown at 93 and 94 in communication with said passages 62, these grooves being closed by rings 95 and 96 suitably welded in place. Hence the passages 92, 93, 94 provide a zigzag conduit through which water may be circulated, suitable inlet and outlet connections `being carried by the bearing shell as indicated at 81 and 98 in Fig. 5. The inlet and outlet pipes for the water are preferably provided with readily disconnectible joints adjacent the shell similar to that of the inlet for high-pressure oil'as shown in Fig. 6. The water circulation thus provided assures that the oil film is maintained sufficiently cool to function properly, because the viscosity of the oil is suitably controlled, or maintained constant if desired, while the hardness of the bearing portion 26 is preserved so that the bearing metal is not softened under the high temperature which might exist in the roll neck under the high unit pressure in the film, if all of the heat had to traverse the length of said bearing portion in lorder to escape.

Referring now to Fig. 4 which shows the radial bearing provided for the neck 2| at the opposite or inner end of the roll, it will be observed that the construction is substantially the same as that described in conjunction with Fig. 3, except that the bearing at this end does not include a thrust bearing, the one thrust bearing at the outer end of the roll being sufficient to sustain the thrust existing on the roll. Rings |60 and |0| are generally similar to rings 41 and 18, with slight modifications. The ring I0| is held in position by a peripheral flange 00|' extending into a corresponding peripheral recess The ring |88 has a split ring |82 secured thereto by screws |02'. The inner periphery of the ring |82 extends into a groove |03 in the roll neck and has all-around clearance relative to the latter. The ring H02 serves to hold the bearings on the neck when the roll is being removed from or replaced in the mill. Otherwise the parts as shown in Fig. 4 are,sub stantally the same and are given the same reference numerals as the corresponding parts in Fig. 3, and have the same function and operation.

As heretofore indicated the bearings for the upper roll are substantially the same as those which have been described in detail in conjunction with Figs. 3 and 4 as applied to the lower roll except that the bearing shells 25 are inverted so that the thicker portions thereof are above the roll necks instead of below as in the case of the shells for the lower roll. In the case of the upper shells, however, the passages for the flow of oil under gravity are of necessity changed with respect to the inverted thicker portions of the shells. Thus the passage by which the oil is led from chamber 84 to chamber 86 is still disposed adjacent the lower portion of the shell where the shell has sufficient thickness to receive the same. With the upper bearings the members i8 take the place of the distance pieces 43 in acting as a support for the tiltable blocks 34.

Referring now to Fig. 8, the complete oil circulation system is shown diagrammatically and includes a head tank |05 which communicates through overflow pipe |06 with sump |01'. lLeading from sump |01 is a pipe |08 which communi- 

